Fluid pressure control



Feb. 7, 1950 s. K. LEHMAN ETAL 2,496,729

FLUID PRESSURE CONTROL Original Filed Nov. 29, 1941 id-3. O f zoe 56 m 60 149- O K i 146 50 Patented Feb. 7, 1950 FLUID PRESSURE CONTROL Samuel K. Lehman, Brooklyn, N. Y., and Donald M. Lawrence, Caldwell, N. J., assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Original application November 29, 1941, Serial No.

421,082, now Patent No. 2,390,487, dated December 4, 1945.

Divided and this application July 14, 1943, Serial No. 494,726

2 Claims. 1

This invention relates to pressure control devices for fluid flow systems, and more particularly to a device for a system for controlling the rate of flow of air to a supercharged aircraft cabin.

This application is a division of our copending application, Serial No. 421,082, filed November 29, 1941, and issued December 4, 1945 as Patent No. 2,390,487.

As scheduled aircraft flight at the higher altitudes is already an accomplished fact, systems have been devised for controlling the pressure and rate of flow of air to the passengers in a sealed and supercharged cabin.

It is an object of the invention to provide a device for a fluid flow control system wherein a desired rate of fluid flow is maintained through pressure sensitive elements operating suitable monitoring servo-motors.

It is another object of the invention to provide a device for a fluid flow control system wherein automatic means are incorporated for preventing the maintenance of excessive rates of flow.

Other objects of the invention include the provision of a pressure sensitive device for permitting the circulation of a working fluid in accordance with predetermined conditions, and the provision of a temperature responsive device for controlling the circulation of a working fluid in accordance with predetermined temperature changes.

Other objects will appear from a study of the following specification when made in conjunction with the attached drawings, throughout which like numerals designate like parts.

Fig. l is an end elevation, with parts in section, of a device constructed in accordance with the invention;

- Fig. 2 is a longitudinal sectional view taken along the line 2-2 of Figure l; and

Fig. 3 is another sectional'view of the device taken along the line 3-3 of Figure 1.

As shown in the drawing, a housing I 3| contains bellows 49 in a chamber I52 and the servo-- valve system having parts heretofore described in the parent application. Chamber 52 has a port I32 formed in one end, which is in communication with a channel I33 formed in housing I3I. This channel terminates in a screw-threaded connection with conduit 55. A similar compartment I is in communication with conduit 54 by means of a channel I34 formed in housing I3I and opening into compartment 5|. Abutments 68 and 69 are shown as cylindrical metal sleeves welded or otherwise attached to the end faces of the end walls of compartments SI and 52, respectively. An initial pressure balance between the compartments 5I and 52 is obtained by means of the helical spring I35, which has one end abutting against the dividing wall 50, and its other end carried in a traveling nut or screw-face plate I36, which is carried on an axially stationary rotatable screw-threaded member I3'I which terminates in an adjusting knob I38 exteriorly of the housing I3'I. The shank portion I39 of screw-threaded member I3! is formed with a smooth cylindrical surface, and has a gas-tight fit with the closure member I40 that is held tightly pressed against housing I3I by means of a plurality of bolts I4I. A guide bar I42 extends through closure I40 and through an aperture in the face plate I36. It will be seen without further explanation that the initial pressure balance for any particular installation may be manually set by means of the adjusting mechanism specified immediately above.

In Fig. l, a crank arm I43 is connected to a shaft I44 which passes through an opening in a wall I56 into a compartment I54 of the housing I3I, which opening is provided with a suitable sleeve bearing I45 and packing gland I46. Crank arm I 43 has a transverse bore I41 in its outer end for connection to the pilots flow-control.

Shaft I44 carries at its inner end an eccentric stub shaft portion or pin member I48, which passes through an intermediate link or beam member I49 (Fig. 3), which is connected at its upper end to rod to through a loose link I50, and at its lower end to a link or lever 58 by means of another loose link I5I. The lever 58 is pivotally mounted at its lower end on a pivot mounting 56 carried by the wall 50. A link 64 is pivotally connected to and between the piston 66 in cylinder 61 and the lever 58, the cylinder having passageway means 91 and H3 at opposite sides of the piston.

Servo-valve members 6| and 62 are carried within valve chamber or receptacle 63, having radially disposed port openings I0 and II, respectively, connected to the pressure channels 13 and I4, respectively.

Upon displacement of the eccentric pin I48 by rotation of crank arm I43 under control of the pilot, the link I49 is translated to the left or to the right, as viewed inFig. 3, and thus, changes the center of rotation of the linkage system controlled by wall connected to servo-valves GI and 62 through the linkage. The valves 6| and 62 are permanently disposed between relief channels I06. The effect of translating the link I49, and therefore, the pivot afforded by pin I48, is the same as that obtained schematically by the vertical motion of link 41 in Fig. 1 of the parent application.

When'the pilot adjusts the flow control, and thus translates the pivot point of link I49 to the right or to the left, as shown in Fig. 3, then dividing wall 50 will be moved toward one of the abutments 58 and 69 acting as means limiting opposite axial movements of the wall, and valves 6! and 62 will be moved from their positions shown in Fig. 3 to permit oil under pressure from channel 72 to be directed into either of the channels 13 or N.

In describing the device of the present invention, only one embodiment has been discussed. It is understood, however, that the invention is not restricted to this exemplary embodiment, but is to be limited only by the scope of the ap pended claims.

What is claimed is:

1. In combination, a housing having a chambet, a compartment, a cylinder and a valve receptacle, an axially stationary rotatable member journaled by and having a screw in and operative from outside the housing, a wall axially movable in the chamber, and carrying a lever pivot mounting, a traveling nut held against rotation on the screw, a spring between the wall and the nut, bellows carrying the wall and extending therefrom to opposite ends of the: chamber, means l miting opposite axial movements of the wall, conduit means communicatin with the bellows at opposite sides of the wall, a piston in the cylinder between. passageway means thereof, a valve axially movable in the valve receptacle carrying axially spaced valve members permanently disposed between relief channels of the receptacle and adapted to control fluid flow between a channel of the housing intermediate the valve members and channels of the housing at opposite sides of the intermediate channel, a shaft rotatable from the exterior of the housing extending laterally of the compartment journaled in a wall thereof and having an eccentric portion therein, a beam intermediately pivoted on the eccentric portion, a lever pivoted to the lever pivot mounting, a link pivotally connected to and between the lever and the beam at one side of the eccentric, a link pivotally connected to and between the valve and the beam at the other side of the eccentric, and a link pivotally connected to and between the piston and the lever.

2. In combination, a housing having a chamher, a compartment, a cylinder and a valve receptacle parallel to each other, an axially stationary rotatable member journaled by and having a screw in and operative from outside the housing, a wall axially movable in the chamber, a guide fixed adjacent to one end of the housing normal to the wall and parallel to the screw, a traveling nut on the screw held against rotation by the guide, a spring between the wall and the nut, bellows carrying the wall and extending therefrom to opposite ends of the chamber, means limiting opposite axial movements of the wall, conduit means providing for communication of the bellows from opposite sides of the wall to high and low fluid velocity points, respectively, an arm fixed to and extending 'axially of the wall in the compartment, a. piston in the cylinder between passageway means thereof and having a rod extending into said compartment, a valve rod axially movable in the valve receptacle carrying axially spaced valve members permanently disposed between relief channels of the receptacle and adapted to control fluid flow between a channel of the housing intermediate the valve members and channels of the housing at opposite sides of the intermediate channel, a shaft rotatable from the exterior of the housing extending later- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,220,972 Fulton Mar. 27, 1917 1,877,576 O'Connor Sept. 13, 1932 2,057,101 Kagi Oct. 13, 1936 2,248,780 Pierce July 8, 1941 2,314,152 Mallory Mar. 16, 1943 2,316,416 Gregg Apr. 13, 1943 

